A shielded coaxial conductor of the type widely used in computers comprises a central conducting core, a sheath of insulating material in surrounding relationship to the core, and a metallic shielding layer in surrounding relationship to the insulation. The shielding layer shields the signals transmitted in the central conductor as its name implies. However, the introduction of the shielding layer requires that the entire conductor must be manufactured with a high degree of precision for the reason that the conductor must have a precisely predetermined impedance Z in order that this quantity can be taken into account in the equipment in which it is used. The impedance is determined by the distance between the central conductor and the shielding layer and the dielectric constant of the insulating material.
The connecting devices used to connect the ends of shielded coaxial conductors to each other must go beyond the mere function of connecting the conducting cores and the shielding layers to each other in separate electrical connections They must also have an impedance which is compatible with the impedance of the cables being connected. If there is a mismatch of impedance between the connection and the impedance of the cables being connected, unpredictable and detrimental effects will result which can frustrate the purpose of the apparatus in which the conductors are used. For example, renegade signals or pulses can be caused by reflection due to an impedance mismatch and these pulses can interfere with the transmission of the intended distorted signals through the cable and in an extreme case can be interpreted as true signals in a distant part of the equipment and thereby completely frustrate its function.
The impedance mismatch problem has been solved for the relatively larger diameter shielded coaxial conductors which have heretofore been used. Usually, the connecting devices comprise pin and socket type connections for both the central core and the shielding material and such devices can be designed to produce acceptable impedance characteristics in the connection. However, future generations of electronic equipment will require shielded conductors of a much smaller diameter than the diameters of the cables or conductors presently used. A conductor is presently being manufactured which has an outside diameter of 0.008 inches (0.2 mm) with the core having a diameter of 0.002 inches (0.05 mm). The known types of connecting devices for shielded coaxial conductors which usually have a diameter of 0.2 inches or more cannot possibly be used for these extremely fine shielded coaxial conductors which are now being designed into future generations of computers. It is simply impossible, as a practical matter, to design a pin and socket type connecting device where the diameter of the central core of the conductor is only 0.05 mm and the outside diameter including the shielding is 0.2 mm.
The present invention is directed to the achievement of electrical connecting devices for shielded coaxial conductors having extremely fine diameters, for example, having an outside diameter of 0.008 inches as noted above. The achievement of this object requires an approach to the problem which is entirely unlike that of known types of pin and socket connectors for shielded coaxial conductors.